I recently acquired 2 used Sartorius 2432 Balances in fairly good condition.
They are identical and seem to have an identical calibration problem.

Both balances are leveled and tared to indicate 0.0 mg. Next the 1 gram
weight from one balance is removed and placed in the pan of the other
balance for weighing.

The "1 gram" knob is placed in the "1" position, and the projected scale
indicates 0.0 mg, indicating that the two scales have identical internal 1
gram weights.

If the "1 gram" knob is then placed to "0," the projected scale should move
to its maximum value, "1/00." It does not. It shows 996.8 mg. I would
like to adjust it to exactly "1/00."

It appears that the downward force of the tare spring is too high. I cannot
find any way to adjust it. I did try temporarily adding a small 1/2-inch
long wire "extender" to the spring to reduce its force, but that did not
help. I am afraid to adjust anything else that I may not be able to reset
properly.

Can someone confirm or refute this analysis, and/or suggest a means of
calibrating the projected scale?

A second question: What are the 4 red tabs that are mounted by red thumb
screws on the top of the mechanism? They seem to be connected to nothing.

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There should be both range and sensitivity adjustments. They are some
knurled weights on threaded screws betwen the pivot and the dampener.
You probably want to play with the sensitivity adjustment.

The small horizonal weight has about 1 turn = 10 mg on range
and the small sensitivity ( scale to 100 ) weight about 1 turn = 0.5
mg. Do not casually play with the larger adjustments.

They are shipping tabs to secure the beam during transport. There
should also be alocking pin that passes throught the beam for one set.
usually the tabs are turned 90 degrees and the screws hand tighened so
they can't interfer with weighing.

Bruce Hamilton

Larry Carr

10-22-2003 01:02 PM

Sartorius 2432 0-200 Gram Analytical Balance Calibration Questions

Bruce,

Thank you very much. You confirmed my suspicions, although the function of
the vertical screws was not obvious at first. The vertical axis screws
control the total full-scale sensitivity of the beam deflection, and the
horizontal screws control the zero point, or tare. There is minor
interaction between them. I was able to set the deflection exactly right
after only a few tries.

Moving the red tabs seems to have no effect, and I do not seem to have a
locking pin, but that is a minor consideration now that I have the scale
calibrated. The two scales were shipped to me by truck without the internal
locking pin, and survived quite well. The 2-gram weight from one scale was
missing, but having two scales, I constructed another 2 gram weight from a
stainless steel bolt and it works very well.